Automatic reclosing circuit-breaker system



July 10 1928. 1,676,316

A. E. ANDERSON AUTOMATIC RECLOSING CIRCUIT. BREAKER SYSTEM OriginalFiled Aug. 25, 1924 Invent or His Attorney Patented July 10, 1928. I

UNlTED STATES PATENT oer-"Ice.

AltVID E. ANDERSON, 01' SCOTIA, NEW YORK, ASSIGNOB TO GENERAL ELECTRICCOIPANY, A CORPORATION NEW YORK.

AUTOIA IIC REGLOBING CIRCUIT-BREAKER SYSTEIQ Application filed August25, 1924, Serial No. 788,918. Renewed February 8, 1927.

My invention relates to automatic reclosing circuit breaker systems andone object of my invention is to provide an improved system foreffecting the closing of a circuit a breaker which is arranged toconnect together twocircuits whenever one of the circuits s energizedand the other circuit is free from short circuits and overloads.

My invention will be better understood In from the following descriptiontaken in connection with the accompanying drawing which shows anautomatic reclosing circuit breaker system embodying my invention, andits scope will be pointed out in the appended claims.

Referring to the drawing, 1 represents a circuit breaker which isarranged to connect together the two conductors 2 and 3 of two 1 directcurrent electric circuits which may be energized independently of eachother by one or more sources of current (not shown). In order tosimplify the drawing, it is assumed that the'ground is the other, sideof both of the circuits which the circuit breaker 1 is arranged toconnect together.

The circuit breaker 1 may be of any suit-- able ty e which is arrangedto be opened upon t e occurrence of a predetermined abnormal conditionon one of the circuits so when the circuit breaker is closed. As shown,the circuit breaker 1 is provided with a closing coil 4, which, whenenergized,

maintains the circuit breaker in its closed position. "trolled by anoverload relay 5 which is connected in any suitable manner so'as to beresponsive to the current flowing between .the two circuits when thecircuit breaker is closed. The relay 5 is arranged so that it to doesnot afl'ect the deenergization of the coil 4 until the current flowingbetween the two circuits exceeds a predetermined value.

The closing of the circuit breaker 1 is controlled by means of areclosing relay fi' which is adapted to control the circuit of the coil4, when the circuit breaker is open, so that it is completed wheneverone circuit is energized and the load, connected to the other circuit isabove a predetermined amount;

.50 The reclosing relay 6 is a difierential relay having a restrainingcoil 8 and an operating coil 9 These two coils are arranged to beconnected so that the relative forces of the two coils va The circuit ofthe coil 4 is conin accordance with the resistance of the (uni whencon-.

nected to one of the circuits w en the circuit breaker'is open and theother e -rcuit is enerized. In m copending application, Serial 0.571,183 ed June 27 1922, I have disclosed and claimed an automaticreclosing circuit breaker system employing a reclosing relay of thistype.

As shown in the drawing, the coil 8 is connected across the" currentlimiting resistor 10, which is connected in series with the conductors 2and 3 when the circuit braker 1 is open, so that the coil 8 is energizedin accordance with the current flowing through the resistor, and thecoil 9 is arranged to be connected between the conductor 2 and ground bythe voltage relay 11 when the voltage between the conductor 2 and groundis above a predetermined value, and be-' tween the conductor 3 andground by the voltage relay 12 when the voltage between the conductor 3and ground is above a predetermined value. The circuits of the volt agerelays 11 and12 preferably are controlled by the circuit breaker 4 sothat they are energized only when the circuit breaker isopen. Alsosuitable means, such as dashpots on the relays 11 and 12, are providedwhereby the circuit of the coil 9 of the relay 6 is not completed untilafter the circuit breaker has been open a certain length of time.

It will be evident, therefore, that whenever the circuit breaker 1 opensdue to a short circuit or an overload on one of the circuits, therestraining coil 8 is energized to maintain the contacts of the relay 6open against the pull of the coil 9, which is connected across thecircuit, which is not overloaded, after the circuit breaker has beenopen for a certain length of time. As soon as the resistance of theoverload has increased above a predetermined value, the actuating coil 9overpowers therestraining coil 8 and eifects the closin'gcof thecircuitbreaker in amaniler hereinafter described,

'In order to prevent the relays 11 and 12 from connecting the conductors2 and 3 directly together in case the contacts of both relays are closedsimultaneously, a resistor 14' is provided. This resistor is arranged sothat it is connected in series with-the coil. 9 when the contacts of oneof the reiays 11 and 12 are closed and is connected inseries he tweenthe eonduetois 2 and-3 when the contacts of bothof the relays 11 and12ers follows "When the circuit breaker,1 is closed and the loadconditions are normal a circuit is completed for the closing coil 4 ofthe circuit breaker 1 from the conductor 3, through the auxiliarycontacts 15 on the circuit breaker 1, contacts 16 of the overload rela5, closing coil t to ground.

Upon the occurrence of an overload or short circuit on one of thecircuits, the overload relay 5 opens its contacts 16whereupon thecircuit breaker 1 opens and inserts the current limiting resistor 10 sothatcurrent flows through the resistor to the overload or short circuit.Since the resistance of the resistor 10 is very high relative to thenormal load resistance, substantially full voltage is impressed on therestraining coil 8 of the reclosing .relay 6 so that this relay cannotclose. its contacts 17.

The closing of the auxiliary contacts 18 on the circuit breaker connectsthe voltage relay 11 between the conductor 2 and ground and the voltagerelay 12 between the conductor 3 and ground. After a predetermined-timethe voltage relay, which is connected to the circuit across which theoverload or short circuit is not connected, closes its contacts,provided this circuit is energized independently of the other circuit.

Let it be assumed, for example, that a short circuit is connectedbetween the conductor 3 and ground and that there is normal voltagebetween conductor 2 and ground. Under these conditions the relay l1closes its contacts 19 but the relay 12 does not close its contacts 20because the voltage between conductor 3 and ground is too low. Theclosing of the contacts 19 connects the actuating coil 9 and theresistor 14 in series between the conductor 2 and ground. The resistor14 is low relative to the resistance of the coil 9. Therefore,substantially normal voltage is impressed across the coil 9. The relay6, however,is designed so that it cannot close its contacts 17 whensubstantially equal voltages are impressed across both coils thereof.

, As the short circuit or overload is re duced, the voltage across therestraining coil 8 decreases but the voltage acro:s the actuating coil 9remains constant so that the relative forces exerted by the two opposingcoils vary with the resistance of the overload or short circuit. Whenthe overload has decreased to a predetermined value, the force exertedby the coil 9 exceeds the restraining force exerted by the coil 8 andthe auxiliary contacts 15 on the circuit breaker- 1, when it is closed,completes the heretofore described circuit for the closing coil 4; andthe opening of the auxiliary contacts 18 de energizes the relays 11 and12 whereupon these two relays and the reclosing relay 6 are restored totheir normal position.

In case the overload or short circuit is between the conductor 2 andground and full voltage is impressed across the conductor 3 and ground,the rela 12 closes its contacts 20 instead of the re ay 11 closing itscontacts 19. Therefore, in this case the actuating coil 9 and theclosing coil 4 are con nected between the conductor 3 and ground insteadof (between the conductor 2 and ground during the reclosing operation ofthe system. a a

It will be observed that in case the contacts-19 and 20 are closedsimultaneously due to the voltage across both circuits being highenough, after the opening of the circuit, to cause both of the relays 11and 12 to operate, the conductors 2 and 3 are connected together throughthe contacts 19 and 20, but the resistor 14 limits the current throughthese contacts to a safe operating value. In my co-pending application,Serial No. 666,- 421 filed October 3, 1923, I have disclosed and claimedanautomatic reclosing circuit breaker system embodying this feature.

While I have, in accordance with the patent statutes, shown anddescribed my invention'as applied to a particular system and asembodying various devices diagrammatically indicated, changes andmodifications will be obvious to those skilled in the art, and I,therefore, aim in the appended claims to cover allsuch changes andmodifications as fall within the true spirit and scope of my invention;

What I claim as new and desire to secure hy Letters Patent of the UnitedStates, 1s: a

1. In an automatic reclosing circuit breaker system, two electriccircuits, 0. circuit breaker arranged to connect .said circuitstogether,- current limiting means arranged to be connected inseries withsaid circuits when said circuit breaker is open, a reclosing relay forcontrolling the closing of said circuit breaker having a voltagewinding, means for connecting said winding to one point on said currentlimiting means while said circuit breaker is open, and means responsiveto a predetermined voltage across one of said electric circuits forconnecting said winding to another point on said cur rent limiting meanswhile said circuit breaker is open.

2. In an automatic reclosing circuit breaker system, two electriccircuits, a c ir cuit breaker arranged to connect said circuitstogether, current limiting means, a reclosin relay for controlling theclosing of said circuit breaker having a voltage wlnding, means forconnecting said winding across one of said electric circuits with saidcurrent limiting means in series therewith after said circuit breakerhas been open for a predetermined length of time, and voltage responsivemeans -for completing a circuit for said relay winding across the otherelectric circuit when the voltage across one of said electric circuitsexceeds a predetermined value after said circuit breaker has been openfor a predetermined length of time.

3. In an automatic reclosing circuit breaker system, two electriccircuits, a circuit breaker for connecting said circuits to"- gether,current limiting means arranged to be connected in series with saidelectrlc circuits when said circuit breaker is open, a reclosing relayfor said circuit breaker having a Volta winding, and means forconnecting sai voltage windin of said reclosing re ay to one pointon,sa1d current limiting means when the voltage of one of said circuitsis above a predetermined value, and for connecting 'said voltage windingto another point on said current limiting means when the voltage of theother one of said circuits is above .a predetermined value.

4. In an automatic reclosin circuit breaker system, two electriccircuits, a circuit breaker for connecting said circuits together, areclosingv relay for said circuit breaker having a voltage winding,current limiting means, and voltage responsive means for connecting saidvoltage winding of said reclosing relay across one of said electriccircuits, with said current limiting means in series therewith when thevoltage across said one of said electric circuits is above apredetermined value, and across the other one of said electric circuitsindepend 'ently of said current limiting means when the voltage acrosssaid other one of said elelctric circuits is above a predetermined vaue.

5. In an automatic reclos' circuit breaker system, two electriccircuits, a circuit breaker for connecting said circuits together,current limiting means arranged to be connected in series with saidelectric circuits when said circuit breaker is open, a differentialrelay for controllingthe reclosing age of the other one of said electriccircuits is above a predetermined value.

- 6. In an automatic reclosing circuit breaker system, two electriccircuits, a circuit breaker for connecting said circuits together,reclosing means for said circuit breaker, a control relay for saidreclosing means having two windings adapted to be connected so that theremoval of a short circuit or overload on one of said circuits when saidcircuit breaker is open automatically changes the relative forcesexerted by said windings, current limiting means, and voltage responsivemeans for connecting one of the windings of said relay across one ofsaid electric circuits with said current limiting means in seriestherewith when the voltage across said one of said electric circuits isabove a predetermined value, and across the other one of said electriccircuits independently of said current'limiting means when the voltageacross said other one of said electric circuits is above a predeterminedvalue.

7. In an automatic reclosing" circuit breaker system, two electriccircults, a circuit breaker for connecting said circuits together,current limiting means arranged to be connected in series with saidcircuits when a said circuit breaker is open, reclosing means for' saidcircuit breaker, a control relay for said reclosing means having twowindings adapted to be connected so that the removal of a short circuitor overload on one of said circuits when said circuit breaker is openautomatically changes the relative forces exerted by said windings,means for connecting one of said windings of said relay to one point onsaid current limiting means 5 and voltage res on'sive. means forconnectin said one c said windings to another point on said currentlimiting means.

8. In an automatic reclosing circuit breaker s stem, two electriccircuits, a circuit breaker for connecting said circuits together,reclosing means for said circuit breaker, a control relag for saidreclosing means having two win ings adapted to e connected so that theremoval of a short circuit or overload on one of said circuits when saiding one of said windings of said relay across no one of said circuitswith said current limiting means in' series therewith after said circuitbreaker has been open a predetermined length of time, and voltageresponsive means for connecting said one of the windings of.

said relay across the'other one of said electric circuits. I

9. In an automatic reclosing circuit breaker system, two electriccircuits, .a circuit breaker for connecting said circuits together,current limiting means arranged to be connected in series with saidelectric circuits when said circuit breaker is open, a differentialrelay for controlling the closing of said circuit breaker having awinding connected so as to be energized in accordance with the currentthrough said current limiting'mea-ns and a voltage winding, a secondcurrent limiting means, and voltage responsive means operative aftersaid circuit breaker has been open' a certain length of time to connectsaid voltage winding across one of said electric circuits with saidsecond current limiting means in series therewith and across the otherone of said electric circuits independently of said second currentlimiting means.

10. In an automatic reclosing circuit breaker system, two electriccircuits, a circuit breaker for connecting said circuits together,current limiting means arranged to be connected in series with saidelectric circuits when said circuit breaker is open, a difierentialrelay for controlling the ,closing of said circuit breaker having awinding connected so as to be energized in accordance with the currentthrough said current limiting means and a voltage winding, a secondcurrent limiting means, a voltage relay connected so as to be responsiveto the voltage across one of said electric circuits and adapted toconnect said second current limiting means and the voltage winding ofsaid differential relay across said one of said electric circuits whenthe voltage across said one of said electric circuits is above apredetermined value, and a second voltage relay connected so as to beresponsive to the voltage across the other one of said electric circuitsand adapted to connect said voltage winding 7 of said differential relayacross said other one of said-electric circuits when the voltage acrosssaid other one of said electric circuits is above a predetermined value.

11. In an automatic reclosing circuit' breaker system, two'ele ctriccircuits, a circuit breaker for connecting said' circuits to gether,means for effecting the opening of said circuit breaker upon theoccurrence of a predeterminedabnormal condition on said circuits,current limiting means arranged to be connected in series with saidcircuits when said circuit breaker is open, a closing coil for saidcircuit breaker, a differential, relay for controlling the circuitof'said closing said circuit breaker in the circuit coil having arestraining winding connected so as to be energized in accordance withthe current through said current limiting means and a voltage winding, atime delay relay arranged to be connected across one of said 10 electriccircuits in response to the opening of said circuit breaker to effectthe connection of said voltage winding of said differential relay to apoint on said current limiting means when the voltage of said one ofsaid electric circuits is above a predetermined value, and a second timedelay relay arranged to be connected across the other one of saidelectric circuits in response to the opening of said circuit breaker toefiect the connection of said voltage winding of said differential relayto a second point on' said current limiting means when the voltage ofsaid other one of said electric circuits is above a predetermined value.

12. In an automatic reclosing circuit breaker system, two electriccircuits, a circuit breaker for connecting said electric circuits, areclosing relay having a voltage winding, means for effecting theopening of 00 said circuit breaker, means responsive to the opening ofsaid circuit breaker for efl'ecting the connection of said voltagewinding across ne of said circuits while said circuit breaker is open,means responsive to the voltage across the other of. said circuits whilesaid circuit breaker is open for connecting said voltage winding acrosssaid other. electric circuit when the voltage thereof is above apredetermined value, and current limiting means connected in series withsaid voltage winding when it is connected to one of said electriccircuits and arranged to be connected in series between said electriccircuits only when said winding is simultaneously connected across bothof said electric circuits.

13. In an automatic reclosing circuit breaker s'stem, two electriccircuits, a circuit brea er for connecting said circuits, means foreffecting the opening of said circuit breaker, a reclosing relay havinga voltage winding for controlling the reclosin of said circuit breaker,a relay arranged w en energized a predetermined amount to connect saidvoltage winding across one of said electric circuits, another relayarranged when energized-a predetermined amount to connect said voltagewinding across the other electric circuits, a circuit for one of 12 saidrelays across one of said electric circuits,

' a circuit for the other relay across the/ other electric circuit, andauxiliary contats on of each relay.

14. In an automatic reclosing circuit breaker s stem, two electriccircuits, a circuit bre er for connecting said circuits, meansfor'eflecting the opening of said circuit breaker, a reclosing relayhaving :1. volt- 139 age winding for controlling the reclosing of saidcircuit breaker, a time relay arranged when energized a predeterminedamount to connect said voltage winding across one of said electriccircuits, another time relay arranged when energized a predeterminedamount to connect said voltage Winding across the other electriccircuit, a circuit for one of said time relays across one of said 10electric circuits, contacts in said time relay circuit arranged to beclosed by said circuit breaker when open, a circuit for the other timerelay across the other electric circuit,

and contacts 1n said last mentioned time relay circuit arranged to beclosed by saidcir- 15 ABVID E. ANDERSON.

